Hi!  I'm trying to make the OATH Toolkit recipe for Guix build the PSKC
parts.  Unfortunately I realized that the GnuTLS backend of xmlsec is
lacking some functionality that is required [1] [2], and that linking
against xmlsec-openssl solves this.  However, Guix doesn't have
xmlsec-openssl, so this patch is necessary before I can suggest a patch
for PSKC support in OATH Toolkit for Guix.

/Simon
[1] https://github.com/lsh123/xmlsec/issues/317
[2] https://gitlab.com/oath-toolkit/oath-toolkit/-/commit/89d144c711e7dcf9c449dacf3ba0d0ba24210a79